Creased sheet metal panel and the method of forming and applying such panels to frame structures



Z'mventor (iittornegs April 22, 1952. A. DAINES CREASED SHEET METAL PANEL AND THE METHOD OF FORMING AND APPLYING SUCH PANELS TO FRAME STRUCTURES Flled March 21, 1950 LELAND A.. DAINES Patented Apr. 22, 1952 CREASED SHEET METAL PANEL AND THE METHOD OF FORMING AND APPLYING SUCH PANELS TOFRAME STRUCTURES Leland A. Daines, Edmonds, Wash.

Application March 21, 1950, Serial N 0. 150,868

My invention relatesto .sheet metal panels; and, more particularly, to creased sheet metal. panels and the method of formingand applying such panels to frame structures.

The article and method are improvements in surfacing structures with sheet metal panels in such a way thatthe panel presents a. uniform outward surface appearance at all times, as distinguished fromsheet. metal panels in prior use, which have their outward surfacequite apparently distorted by changes in temperature, rack", ing of the frame, and.the like. The method of maintaining the uniform outward surface, briefly, comprises bowing a sheetmetal covering panel by creasing the same along a plurality of parallel spaced-apart lines between opposite edgestheree of, applying said bowed panel .to a frame structure so that the convexly arcuate face is against said frame, and securing the panel to the frame so that the creases areppartially. fiattenedand the spaces between the creases are caused to assume outwardly bowed slightly convex curvatures. On expansion or contraction of the panel due to changes in temperatures, expansion and contraction is localized between the creases and dissipated in slight inwardor outwardmovement of the convex curvatures.

Many structures are covered by panels of sheet metal. A common example isthe covering of closed truck bodies. Where plain panels are used, these bodies often present a somewhat unsightly appearance due to apparent bowing in such sheet metal coverings, causing light to be reflected unevenly. The impression given is that the frame structure of the body is distorted or that the metal covering is not well secured to the frame. The distortion is usually not due to unevenness of the frame structure, which is often most solidly built, and is not due to lack of securing means for the panel, as many means are employed to afford ample anchoring of the panel to the frame. The unevenappearance is caused by expansion and contraction of the sheet metal due to changes in surrounding air temper: atures. The apparent bowing of the panel between the points of securing is difficult to prevent. The frame studding and stringers form the principal points to which the sheet metal may be secured. Between these points of, securing to the frame occurs the bowing that causes the uneven reflection of light.

The visible effect of panel bowing canbe minimized by using an irregular panel, such as corrugated galvanized iron but distortion is still apparent.

3 Claims. (01. 296-28) Especially in metallic structures, such asbodies of vehicles, considerable noise iscaused ,bythe movement of .the sheet metal structure against the frame at points which are not secured. Unpleasant rumbling and rattling noises mayube caused by the action of wind on unsecured portions of a sheet metal covering, and these may also occur on non-movable structures.

The objects of my invention include: devising a method of applying sheet metal panels to structures so that a uniform outward surface appearance is presentedthroughout changes in temperatures; forming a sheet metal panel of such design that distortion due to expansion and contraction of the ,metal during temperature changes is so distributed and localized that no apparent bowing of the panel occurs; construct:v ing a sheet metal covering in a form so that the covering will be bowedand, when secured to a structure with the convex face inward, said face will be compressed against the structure and there will be resistance to relative movement between thecovering and the structure whereby noise due to such relative movement will be avoided; and providing in a sheet metal panel of economical design and sturdy construction having a long life, a shape whereby the panel pre sents a uniform outward surface. 7

The method, in brief, whereby the foregoing objects are met is as follows: I prefer to formmy creased sheet metal panels of aluminum or aluminum alloys but other sheet metal material may be substituted. A plurality of parallel, spaced-apart creases, between opposite edges thereof and parallel to the other edges, is formed in the sheet metal with the crests of said crease on a common face of the panel whereby the opposite face thereof is bowed concavely.

One edge of the panel is attached to the frame structure to be covered, with the crests toward the frame. Then the rest of the panel is pressed to the structure so that the creases abutting the 'frame are partially flattened and the spaces between the creases on the outward face are caused to assume slightly outwardly bowed sur faces. placed under tension and the inner surface is placed under compression. H l H Upon expansion orcontraction of the panel, upon changes intemperature, the spaces between the creases may bow in or out but the bowing'is generally uniform in each space and no noticeable change occurs. The uniformity of the surface is in marked contrast to the apparent dlstortion of the usual sheet metal panels.

The outward surface of said spaces is horizontally onithe sides;

preferred because of the attractive. appearance The intermediate creases in the panel may be creased more sharply than the marginal creases, in which case the bow of the sheet is more parabolic than uniform. When the sheet is pressed against the frame, there is more pressure in the center of the sheet than near the edges, which is a desirable feature in that the center usually suffers the most distortion in the usual sheet metal panel."

Each crest of the creases being pressed against .the frame structure, resistance against relative movement between the panel and the structure eliminates noise usually madebysucl'fmovement;v

which is important, especially in coverings for: vehicles.

My invention will be understoodbestfromthe" following description, when read in connection- 7 with the accompanying drawings, in which:

Figure 1 is a perspective view of a truck: andpresented by the: multiple horizontal lines and because when the horizontal. panels are overlapped, one over anothen rainwill not enter between the panels andinsidebody l2,..evenin the absenceof sealing materials; Greased. panels may-also cover the top-of body I 2.

In Figure 2 is shown inmore detail the covering of 'a truckbody. Theskeletonframestructure of the-truck body includes stringersi l4, bed- [6 positioned on said strin'gers-guards H! on the. edges of the bed, uprights and joist 22. Covering the skeleton-framestructure arecreased sheet metal panels 2L Thepanels may be made of various metals but itis preferred that they be; light weight and" have resilient qualitiesas well-asg'oodability tostand exposure to weather without-eXcessive-deterioration.

Several factors enter into the decision as to the-spacing of the-cr'easesin the panel, It may be desirable to have the creasesspaced acertaindistance because of aesthetic considerations or to have evenly spaced creases on a surface of a predetermined width; In general, the fewer creases the less the cost of formingthepanel. Distortion of the panel in a direction perpendicular to its surface is uniformin each space between creases; as-will be-more fully developed later, due to the-fact that the crest-of'eachcrease ispressed against the'skelt'on frame structure as v the panel, originally of bowed shape, issecured to a fi'atframework; Therefore, it isnecessary to have the creases close enough together to maintain" the phenomenon of even distribution of distortion;

The details of-the paneland the method of securing the same is most clearly depicted in Figure 3. Fragments of theskeleton frame of a truck body shown include bed 26, guard 28 on the edge of the bed, upright 30,- bracket 32, joist 34 and corner piece 36; Portions of three panels 38" are shown. Each panel has formed therein; as by pressing, a' plur'ality of parallel; longitudi 4 nally-extending, spaced-apart creases 40, with the crests 42 all disposed on a common face of the sheet metal wall covering panel 38.

Before the panels are secured to the frame, they are longitudinally bowed with the crests disposed on a convexly arcuate face, as at 44 in Figure 2. When the panels are secured to a frame structure the crests. are positioned abutting the outer surface of the" frame to' becovered and are somewhat flattened. Crests 42 press 7 against the frame with considerable force, which explainsthe absence of the noise usually incidentt'o the covering'of a vehicle body by metal panels due t'o the striking of the panels against the frame as the truck body sways and bumps. Drivers of vehicles covered by my new creased panelshave remarked on the absence of the noise incident to the use of the usual plain metal covering f'or'vehicles.

The space 46 between creases 40 is outwardly bowed. witha: convex curvature, the outer surfacei48 being under tension and the inner face 50 beingaunder compression.

One of the main features of my'invention is the localization of distortion of thepanels'38, due to. temperature changes, whereby outer surface 48 ineach'space ifi between creases 40, moves in:

wardly oroutwardly a uniform distance; Uneven distortion of theusual metal: panel during;

temperature changes, causes unsightly appear-' ance aslight reflects: unevenly from the panel. In the present: panel, little tendency is' present to concentrate the distortion intone'area as all areas are under pressure and: have about the same resistance: to distortion; Each space 46' between creases movesi inwardly or outwardly,

when there isa temperaturechange; about the same distance; and, the distance being. small, the distortion isnot apparent;

The marginal creases do: not need. to: be formed as sharply as. the intermediatecreases as. the securing means near the margin: assist the marginal portion in -re'sisting distortiom Therefore, it; may be preferred: to have intermediate: creases formed more sharply than marginal creases, in which case an unsecured panel. is longitudinally bowe'dmore" parabolic than uniform, as is sh'o'wn at'Min' FigureZ; Morepressure is --pla'c'edon the crestsof the intermediate:

creases-asthey abut theframe structureto which they are secured; and there is more resistance to relative movement between said crests and said structure; at these points farthest from the m'a'rgi'nal edgewhere the panel is secured, and the crestsand' structuremove as one piece whereby no noise iscreated as the vehicle moves.

One means of securingthecreased sheet metal panels to a' structure-is illusti'atedin- Figure 3.

Panels 38 are'lapped and screws 52 r unthroughthe lapped joint, there being washers 54 on the screwsi At the upper corners of the truckbody is" a transversely curved member 56 lapped at its upper edge by'one panel and lapping at its lower edge the panel on the side-wall. The

lowest panelis lapped' over the upper end of guard 28 at 58.

Method of applying the sheet metal panels InFigure 2 is shown a single panel. covering the sidewalls of a vehicle-body skeleton structure. The drawing shows a-sid'ewall panel; at 44, partially'secured to the frame structure. Takingfa sheet metal'panel, creased along a iurautyor parallel spaced-apartlinesextendingbetween'op- 'posite edges thereof and parallel to the other edges, one edge is secured to the frame skeleton. The convexly arcuate face with the crests of the creases is directed toward the structure. Then the panel is unbowed by pressing the same to the frame structure so that the crests abut the frame structure and the creases are partially flattened, and the spaces between the creases on that face directed away from the frame structure are caused to assume outwardly bowed slightly convex curvatures. The panel is secured to the frame structure in this position.

Upon the occurrence of expansion or contraction of the sheet material, the forces thereof are localized between the creases and dissipated in outward or inward movement of the outwardly bowed slightly convex portions of the sheet metal panels.

Reflection from the outer surface of the creased panel is then substantially uniform throughout all changes in temperature. creases in the panel tightly abut the frame structure so there is little possibility of relative movement therebetween and no noise is created by one moving against the other during movement of the vehicle.

It is preferable, especially when wide panels are being used, to form the intermediate creases more sharply than the marginal creases, whereby the bow is more parabolic than uniform, and, when the sheet is pressed to the frame structure, there is increased pressure at the intermediateridges over the pressures pertaining with the marginal ridges, whereby it is insured that the central, unsecured portion will tightly abut the frame structure.

Various modifications of the specific embodiment shown and described will be apparent to those skilled in the art, without departing from the spirit of the invention, and I do not wish to be understood as limiting myself to said specific embodiment.

Having thus described my invention, I claim:

1. In the application of sheet metal panels to frame structures, the method, comprising: bowing a sheet metal panel so that one face is convexly arcuate by creasing the same along a series of parallel, equidistantly spaced-apart lines extending between opposite ends thereof and parallel to the sides thereof with the crests of the creases all disposed on a common face of the panel, applying said bowed panel to a frame structure so that the convexly arcuate face is directed The crests of the toward the frame structure, securing one of the side edges alongside the creases to said frame structure from end to end, then unbowing said panel by pressing the same to said frame structure so that the creases abut the frame structure and are partially flattened and the spaces between the creases on that face directed away from the frame structure are caused to assume outwardly bowed slightly convex curvatures, and securing said sheet to the frame structure in said unbowed relationship, whereby upon the occurrence of expansion or contraction of the sheet material the forces thereof are localized between the creases and dissipated in outward or inward movement of the outwardly bowed slightly convex portions. of the sheet metal panels therebetween.

2. In the method of claim 1 in which, in the bowing of thesheet metal panel by creasing the same, the intermediate creases are formed more sharply than the marginal creases of said plurality whereby the bow is more parabolic than uniform and, when the sheet is pressed to the frame structure there is increased pressure at the intermediate ridges over the pressures pertaining with the marginal ridges.

3. A vehicle body, comprising: a skeleton frame structure, and a sheet metal covering panel on said frame structure, said panel being characterized by having a series of like creases extending between opposite edges of the panel, the crests of said creases being on the inner face of said panel and being tightly pressed against said frame structure by, internal strain in said panel, the panel between said creases being outwardly bowed and the outer faces of said outwardly bowed portions between said creases being under tension and the opposite inner faces thereof being under compression.

LELAND A. DAINES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,631 Naylor June 12, 1840 1,472,128 Manly et a1 Oct. 30, 1923 2,330,182 Theriault Sept. 21, 1943 2,477,987 Kinghorn Aug. 2, 1949 2,513,473 Greig July 4, 1950 

